Although printers typically are used to print on media of various media sizes, most printers have a maximum media width capacity, and correspondingly, a minimum media width on which effective printing can be accomplished. Some printers, such as high speed laser printers, provide dedicated input media trays for each media size. Lower cost printers, such as mass-market inkjet printers, generally have only one tray, typically accommodating letter-size media (8.5″×11″), with some adaptability to accommodate printing on media of different sizes.
In order to accommodate printing on media of different width media, printers often employ adjustable media edge stops that slide to constrain the side edges of narrower media sheets. Printing on media shorter than standard letter-size length normally is accommodated by feeding a stack of the shorter media into an input tray until its leading edge abuts a stop. While this has proven workable in some instances to accommodate envelopes and smaller index cards, there have been disadvantages to this approach.
Some printers, for example, have input trays that are not removable, and which extend well into the body of the printer. This leaves a significant distance between the media insertion aperture and the leading edge stop. It thus may be difficult to load or extract media which is shorter than this distance. Furthermore, it may be difficult to adjust the media edge stop in a manner necessary to maintain the media in its proper lateral position.
A further difficulty in accommodating smaller media sizes is that many printers rely on a common media registration scheme, such as using one edge of a media tray as a fixed side edge reference for all media sizes. Any measures to accommodate smaller media that do not provide contact with this reference surface will require printer firmware changes, generating cost and complexity disadvantages.
Additionally, even printers which do overcome problems with loading smaller media may not be adequately adjustable in width, leading to problems of unacceptable media skew. For example, media edge stops typically are adapted to engage a central region of standard size media sheets, laterally biasing the media in order to maintain proper input stack orientation. It will be appreciated, however, that smaller media typically is engaged nearer a trailing end of the media, potentially skewing the media as it enters the insertion aperture. This may be exacerbated as the input tray floor pivots upward, making it difficult to maintain a lateral biasing force on the input media stack.